• Title/Summary/Keyword: 공분산 구조

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A Stagewise Approach to Structural Equation Modeling (구조식 모형에 대한 단계적 접근)

  • Lee, Bora;Park, Changsoon
    • The Korean Journal of Applied Statistics
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    • v.28 no.1
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    • pp.61-74
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    • 2015
  • Structural equation modeling (SEM) is a widely used in social sciences such as education, business administration, and psychology. In SEM, the latent variable score is the estimate of the latent variable which cannot be observed directly. This study uses stagewise structural equation modeling(stagewise SEM; SSEM) by partitioning the whole model into several stages. The traditional estimation method minimizes the discrepancy function using the variance-covariance of all observed variables. This method can lead to inappropriate situations where exogenous latent variables may be affected by endogenous latent variables. The SSEM approach can avoid such situations and reduce the complexity of the whole SEM in estimating parameters.

Maximum likelihood estimation in multivariate structural model (다변량구조모형에서 최대우도추정)

  • 김기영
    • The Korean Journal of Applied Statistics
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    • v.1 no.1
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    • pp.39-44
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    • 1987
  • For obtaining the m.l.e. of $\Sigma$ from p-variate Non-singular Normal parent, $N_p(\mu, \Sigma)$, Andersous' Procedure based on the invariance property of the m.l.e. seems to be generally Preferred in the view of its simplicity. This paper shows that his approach with respect to $\Sigma^{-1}$ rather than $\Sigma$ itself, he burther applicable to deriving the m.l.e. of parametersinvolved in the common factor model an dsimplex model as well.

Structural Relation between Antecedents and Consequences of Web Site's Trust of Venture Company (벤처기업의 웹사이트에 대한신뢰의 선행요인과 결과요인의 구조적 관계)

  • Kwak, Won Seob
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.8 no.4
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    • pp.25-35
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    • 2013
  • The main objective of this study is to investigate the structural relation between antecedents and consequences of web sites' trust of venture company. It examines consumer perceptions trust in a web site and address following research questions; what factors influence consumer trust in a web site and what specific web site cues are associated with trust, satisfaction, and intention? We test our hypothesis in a empirical data from 123 consumers across 3 web sites of venture companies. By factor analysis, the results show that web site characteristics are such as design, business function, interface, technology, community, and contents of each web site. We also find that web site characteristics such as design, interface, technology, and community can influence significantly satisfaction of web site, and design and contents of web site can influence consumer's trust. And the results show that trust influence behavioral intention through the satisfaction. The results offer important implication for web site strategies of venture company that include the manipulation of factors influencing web site trust. And the future directions of the present research are discussed.

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A Study on Groundwater Contamination Potential of Pyungtaek-Gun Area, Kyunggi-Do Using GIS (GIS를 이용한 경기도 평택군 지역의 지하수 오염 가능성 평가 연구)

  • 조시범;민경덕;우남칠;이사로
    • Journal of the Korean Society of Groundwater Environment
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    • v.6 no.2
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    • pp.87-94
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    • 1999
  • This study is providing Modified DRASTIC Model to which lineament density and land use are added as additional factors using geographic infomation system(GIS). and then to evaluate groundwater contamination potential of Pyungtek-Gun area in Kyunggi-Do. In this study. the reason for using additional factors is because. in case of lineament density. when we consider that most of aquifer is bedrock aquifer in hydrogeologic environment of the Korea, lineament is very important to flow of groundwater and contamination material. and because land use can reflect indirectly impact of point or non_point source in study area. For statistical analysis. vector coverage per each factor is converted to grid layer and after each correlation coefficient between factors, covariance, variance. eigenvalue and eigenvector by principal component analysis of 3 direction. are calculated. correlation between factors is analyzed. Also after correlation coefficients between general DRASTIC layer and rated lineament density layer and between general DRASTIC layer and rated land use layer are calculated. final modified DRASTIC Model is constructed by using them with each weighting. when modified DRASTIC Model was compared with general DRASTIC Model, comtamination potential in modified DRASTIC Model is fairly detailed and consequently. vulnerable area which has high contamination potential could be presented concretly.

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Effects of environmental management on firm performance (환경경영이 경영성과에 미치는 영향에 관한 연구)

  • Kang, Min-Seok;Choi, Hyun-Seok;Park, Byung-Chun
    • Journal of the Korean Data and Information Science Society
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    • v.22 no.3
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    • pp.523-536
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    • 2011
  • This study is to empirically investigate structural relations and the degree of effects among environmental strategy, environmental management system, environmental activities, and firm performance by using structural equation modelling. In particular, we focus on examining how the structure and the effect vary according to the type of environmental strategies. In this study, environmental strategies are classified as "passive type" and "active type" by the cluster analysis, which are used for developing two different research models. For firms employing active environmental strategy, the environmental strategy has a positive effect on all of environmental management system, environmental activities, and firm performance. For firms employing passive environmental strategy, the environmental strategy has a positive effect on both of environmental management system and environmental activities, while it does not have a statistically significant effect on firm performance. The study empirically supports that the active environmental management will result in a positive firm performance.

Relationship among Followership, Organizational Cynicism, Organizational Citizenship Behavior in Hotel Employee (호텔기업 구성원의 팔로워십, 조직냉소주의, 조직시민행동 영향 관계)

  • Chung, Hyun-Young;Lee, Sang-Woo
    • The Journal of the Korea Contents Association
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    • v.11 no.7
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    • pp.448-457
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    • 2011
  • The purpose of this research investigates the relationship among followership, organizational cynicism, and organizational citizenship behavior in Hotel employee. The data are analyzed by such frequency analysis, exploratory factor analysis, reliability analysis, confirmatory factor analysis, covariance structure analysis. The SPSS 10.1 and AMOS 4.0 for Windows program was used to investigate material. The major finding and implication can be summarized as follow: First, the analysis on relationship between followership and organizational cynicism revealed that critical thinking and active participation dimensions of but enthusiasm dimension of followership has not affected organizational citizenship behavior. Second, the analysis on relationship between organizational cynicism and organizational citizenship behavior revealed that organizational cynicism affects organizational citizenship behavior.

Supercompact Multiwavelets for Three Dimensional Flow Field Simulation (3차원 유동 시뮬레이션을 위한 Supercompact 다중 웨이블릿)

  • Yang, Seung-Cheol;Lee, Do-Hyung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.12
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    • pp.18-25
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    • 2005
  • This paper presents a supercompact multi-wavelet scheme and its application to fluid simulation data. The supercompact wavelet method is an appropriate wavelet for fluid simulation data in the sense that it can provide compact support and avoid unnecessary interaction with remotely located data (e.g. across a shock discontinuity or vortices). thresholding for data compression is applied based on a covariance vector structure of multi-wavelets. The extension of this scheme to three dimensions is analyzed. The numerical tests demonstrate that it can allow various analytic advantages as well as large data compression ratios in actual practice.

User Acceptance Factors of u-Health System - For Converged Smart Health (유헬스 시스템의 사용자 수용 요인 연구 - 융합형 양방향 스마트 헬스를 위한)

  • Kim, Mincheol
    • Journal of Digital Convergence
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    • v.11 no.4
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    • pp.321-330
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    • 2013
  • Lately, in accordance with the improvement of living standards and income level, concern about the health is continuously increasing and the desire is also becoming diverse. This study focused on the user's acceptance of converged smart u-health system. For the study purpose, this paper analyzed the health and technology factors influencing the user's acceptance on u-health system. Thus this study was carried out by using covariance based SEM in order to test the model fitness and path coefficient. As the results, the health management experience among HPM factors and perceived usefulness among TAM had a positive effect on attitude and the perceived usefulness had a direct effect on behavioral intention.

Subspace-Based Adaptive Beamforming with Off-Diagonal Elements (비 대각요소를 이용한 부공간에서의 적응 빔 형성 기법)

  • Choi Yang-Ho;Eom Jae-Hyuck
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.1A
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    • pp.84-92
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    • 2004
  • Eigenstructure-based adaptive beamfoming has advantages of fast convergence and the insentivity to errors in the arrival angle of the desired signal. Eigen-decomposing the sample matrix to extract a basis for the Sl (signal plus interference) subspace, however, is very computationally expensive. In this paper, we present a simple subspace based beamforming which utilizes off-diagonal elements of the sample matrix to estimate the Sl subspace. The outputs of overlapped subarrays are combined to produce the final adaptive output, which improves SINR (signal-to-interference-plus-noise ratio) comapred to exploiting a single subarray. The proposed adaptive beamformer, which employs an efficient angle estimation is very roubust to errors in both the arrival angles and the number of the incident signals, while the eigenstructure-based beamforer suffers from severe performance degradation.

Approximated Constrained Least Squares Filter for Real-Time Directionally Adaptive Image Restoration (제약적 최소 제곱 필터의 근사화를 이용한 실시간 방향 적응적 영상복원)

  • Cho, Changhun;Jeon, Jaehwan;Paik, Joonki
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.12
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    • pp.150-158
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    • 2013
  • In this paper we present approximated constrained least squares filter for real-time directionally adaptive image restoration. The proposed method makes a hardware implementation easier for real-time image restoration because of reducing the filter size. Furthermore, for directional adaptive image restoration, this paper estimates the local orientation by analyzing the covariance matrix and applies to approximated constrained least squares filter. Experimental results show that the proposed method is sharper and less artifacts than existing methods.